1. Field of the Invention
The present invention relates to trench boxes. More particularly, the present invention the relates to panel assemblies as used in such trench boxes. Additionally, the present invention relates to connector arrangements whereby one panel of the trench box can be flexibly and securely mounted to another panel of the trench box.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
The construction industry often desires to employ excavations of various types, such as foundations, trenches, and the like. Where excavations are made in the earth, it is desirable to support the upright sidewalls of the excavation against collapse or to protect a sheltered workspace in the event of collapse. Due to unstable soil conditions, improper sloping of an excavation and/or other unaccounted-for occurrences, landslides, and cave-ins ensue. These natural occurrences have been known to destroy equipment, postpone job completion and, more seriously, injure or kill the workers within the excavation. Consequently, trench excavation is recognized by the Occupational Safety and Health Administration as being an extremely hazardous construction operation and it has promulgated regulations directed to the manner in which excavations are created and to the structures used to support the excavation against side wall collapse.
The current practice in the industry is to place trench boxes inside an excavation site. The trench boxes are generally open at the bottom so that the excavation can continue while the boxes are in place and open at the top for easy access by men and machinery and easy removal of excavated materials. The primary structure of a trench box is comprised of opposing side panels that perform a shoring or shielding function by holding the side walls of the excavation in place so as to prevent the side walls from collapsing into the trench or hole in the ground created by excavating. Additionally, trench boxes usually have a plurality of bars or beams that traverse the lateral width of the trench box, attaching to opposing trench box panels and reinforcing or supporting the opposing panels, thus providing further protection from side wall collapse. These support bars are also known as spreader bars as they assist in keeping the panels sufficiently spread apart from each other.
It is often desirable that the width between the opposing panels be changed. Additionally, the trench boxes usually have a fixed width in which the spreader bars are rigidly secured, by welding, or otherwise, to the opposing side panels. When damage occurs to the trench boxes, it is very difficult to repair or replace the various components. Since the panels are secured to the welded collars, they occupy a great deal of space during transport and storage. Additionally, when damage occurs, it is very difficult to repair such trench boxes on-site.
Additionally, trench boxes that have fixed side walls and spreader bars are often very difficult to move. Conventionally, when the side panels bear against the earth formation, the frictional effect created thereby strongly resists any movement. As such, a need has developed whereby the trench boxes can be more easily manipulated so as to reduce this frictional effect and allow for an easier movement of the trench box from one location to another.
In the past, various patents have issued relating to such trench boxes. For example, U.S. Pat. No. 3,992,887, issued on Nov. 23, 1976 to W. A. Fisher, describes a trench shoring assembly with a force transferring accessory. There is a pair of spaced-apart side walls for vertical disposition within a trench. Spreader pipes and spreader collars interconnect the side walls and allow limited pivotal movement between the walls. Each side wall includes inner and outer metal plates connected to a plurality of interconnected structural members so as to define a main frame. The interconnected structural members include horizontally extending hollow metal beams including a top beam which extends longitudinally along the top of the side wall, a pair of intermediate beams parallel the hollow metal beam and a bottom beam.
U.S. Pat. Nos. 4,033,138, 4,044,564 and 4,056,938, issued to J. L Griswold, describe trench shoring assemblies with a stacking accessory. A hardwood insert is disposed within the top beam of the wall to prevent a collapse of the metal beam. A number of hollow beams extend perpendicularly to the horizontal beams and ribbed members extend perpendicularly to the horizontal beams. The side walls of the assembly have a tapered bottom portion which defines a triangularly-shaped pointed lower extremity extending between the ends of the bottom portion. A metallic bar is disposed at the pointed lower extremity and extends between the ends of the bottom portion and protects the bottom of the side wall against abrasion. A U-shaped member is welded to the main frame, and, in turn, a spreader collar is welded to the U-shaped member so that a force applied to the spreader collar is transferred directly to the main frame. Each spreader pipe spaces the side walls apart between two spreader collars to which the spreader pipe is attached by spreader pins. A plurality of flanges extend from a spreader pipe and are connected by locking pins to mating flanges which extend from another spreader pipe of another vertically stacked trench shoring assembly.
U.S. Pat. No. 4,056,940, issued on Nov. 8, 1977 to W. A. Fisher, shows a trench shoring assembly having first and second spaced walls having upper surfaces with third and fourth spaced walls stacked upon the upper surfaces of the first and second walls. A plurality of tubular collars project from the various walls and are aligned vertically at each end thereof. Spreader pipes interconnect these collar projections at one end of the assembly and a spreader assembly interconnects the stacked walls at the other end. The spreader assembly includes vertically-extending metal beams interconnecting the collars projecting from the walls and tie bars extending between the vertical beams at a position spaced well above the upper surfaces of the lower walls.
U.S. Pat. No. 4,259,028, issued on Mar. 31, 1981 to J. B. Cook, provides water and debris impermeable trench box panels. A lightweight foamed filler is located between the inner and outer panel surfaces in a trench box panel and between structural, vertical and horizontal elements.
U.S. Pat. No. 4,993,880, issued on Feb. 19, 1991 to J. Collins, describes a trench-box panel having an array of horizontal elongate “C-section” members one on top of another and welded together continuously along their lengths. The members are longitudinally staggered to leave spaces between the ends of alternate members at each side of the panel. Robust vertical angle-members and flat members are welded to the ends of the horizontal members to seal the ends of cavities inside the horizontal members.
U.S. Pat. No. 7,559,724, issued on Jul. 14, 2009 to J. D. Olen, teaches an adjustable and portable trench support for placement within a trench. This trench support includes a pair of support panels disposed within the trench and against the opposed trench walls. Support plates include, on their interior sides, a pair of support arm guides. Each support arm guide has a vertical channel and a number of offsets so that support arms can be slid within the channels and vertically positioned in the desired offsets. The pair of support arms are mounted to the support arm guides in support plate so as to have larger diameters than the support arms mounted to the opposite support arm guides so as to allow for the telescopic slidable insertion of the smaller diameter support arms into the larger diameter support arms.
U.S. Pat. No. 7,837,413, issued on Nov. 23, 2010 to R. Kundel, Sr., shows an adjustable trench box and spreader bar assembly which has male and female telescoping pipes. The male telescoping pipe has a plurality of indexed openings. The female telescoping pipe has an outer threaded portion with a groove to receive a locking pin. A sleeve is threadedly attached to the outer threaded portion of the female telescoping pipe. The sleeve has a sleeve opening and an inside channel for receiving the locking pin therethrough such that fine adjustments in the relationship between opposing panels of the trench box can be made by rotating the sleeve about the threaded portion of the female pipe for extension or retraction of the male pipe.
It is an object of the present invention to provide a trench box assembly that is easily stackable.
It is another object of the present invention to provide a trench box assembly that can be disassembled into a very compact configuration.
It is still another object of the present invention to provide a trench box assembly which is safer to transport.
It is still another object of the present invention to provide a trench box assembly wherein the components of the trench box assembly are reversible.
It is still another object of the present invention to provide a trench box assembly that provides greater flexibility at the joints between the spreader bars and the panels of the trench box.
It is still a further object of the present invention to provide a trench box assembly that is easier to dislodge and move when installed in the earth.
It is still a further object of the present invention to provide a trench box assembly which is easier to repair.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.